1. Technical Field
This application relates to semiconductor memory and, in particular, to relinking of metablocks.
2. Related Art
Arrays of nonvolatile memory cells in semiconductor memory may be divided into groups to provide for efficient implementation of read, program and erase functions. For example, the memory cells may be arranged into a group called a unit of erase.
The unit of erase may be the smallest number of memory cells that are erasable at a time. An example of the unit of erase may be a block.
The block may be referred to as a physical block to distinguish the physical block from a logical block of a block storage device. A file system may map each logical block of a block storage device to one or more corresponding physical blocks. The file system may map files to logical blocks, which are mapped to the physical blocks.
The physical block may be partitioned into individually addressable pages. Pages may be the basic unit for reading and programming user data (unit of reading and/or programming).
In some examples, the physical blocks may be grouped together to form metablocks or “super” blocks. The metablocks may be considered a physical construct even though the metablocks are logical groupings of physical blocks. This is because the file system may map each logical block of a block storage device to a corresponding metablock as if the metablock were a large physical block.
Using metablocks may improve the reliability of the semiconductor memory because the physical blocks of the metablock may be distributed across physical structures of the semiconductor memory, such as dies and/or planes. Read and/or write speeds of the semiconductor may also be improved with metablocks because the physical block on each respective physical structure may be read and/or written in parallel with the blocks of the metablock on the other physical structures. However, if any of the physical blocks of the metablock becomes defective, then the metablock may be mapped to an entirely new set of physical blocks. As a result, the original physical blocks of the metablock that were not defective may no longer be used, thereby reducing the overall life of the semiconductor memory.